id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
10270,square root of boost units scaled_unit fails to compile,sharifmarat@…,Matthias Schabel,"I have created a scaled unit to handle micro meters:
{{{
typedef make_scaled_unit<si::length,
                         scale<10, static_rational<-6> > >::type micro_meter_unit;
}}}

Everything works as expected:

{{{
quantity<si::length, double> some_meter = 10 * si::meter;
quantity<micro_meter_unit, double> some_mu_meter = 
  static_cast<quantity<micro_meter_unit, double>>(some_meter);

std::cout << ""some_meter^2 = "" << some_meter * some_meter;  // outputs 100 m^2
std::cout << ""some_mu_meter^2 = "" << some_mu_meter * some_mu_meter; // outputs 1e+014 p(m^2)
}}}

Yet the square root operations is not compiled:

{{{
std::cout << ""sqrt(some_meter) = "" << sqrt(some_meter); // outputs 3.16228 m^(1/2)
std::cout << ""sqrt(some_mu_meter) = "" << sqrt(some_mu_meter); //error here
// 'value' : is not a member of 'boost::units::scale_dim_tag'
}}}

Also the following code fails to compile:

{{{
quantity<si::length, double> mu_meter(sqrt(1.0 * si::micro * si::meter * si::meter));
}}}

I used the following include files:

{{{
#include <iostream>
#include <boost/units/quantity.hpp>
#include <boost/units/make_scaled_unit.hpp>
#include <boost/units/systems/si.hpp>
#include <boost/units/cmath.hpp>
#include <boost/units/io.hpp>
#include <boost/units/scale.hpp>
#include <boost/units/systems/si/prefixes.hpp>
}}}",Bugs,closed,To Be Determined,units,Boost Development Trunk,Problem,fixed,scale,